1. Field of the Invention
The present invention is related to a method for inspecting a photo-mask, and more particularly, to a method for inspecting a photo-mask focusing on the anchor point of the photo-mask.
2. Description of the Prior Art
In modern society, micro-processor systems composed of integrated circuits (IC) are ubiquitous devices, utilized in such diverse fields as automatic control electronics, mobile communication devices and personal computers. With the development of technology and the increasingly imaginative applications of electrical products, the IC devices become smaller, more delicate and more diversified.
In the semiconductor manufacturing processes, in order to transfer an integrated circuit layout onto a semiconductor wafer, the integrated circuit layout is first designed and formed as a photo-mask pattern. The photo-mask pattern is then proportionally transferred to a photoresist layer positioned on the semiconductor wafer. It is understood that the quality of the photo-mask may influence the critical dimension uniformity (CDU) of a wafer.
To ensure that the photo-mask can be successfully utilized in a lithography system, after the photo-mask is manufactured, an inspection process is usually carried out to check if there are defects on the photo-mask. The inspection process can ensure that the quality of the photo-mask can meet the target of the semiconductor manufacturing process. However, currently, there are no sufficient inspection methods that can help the manufacturers to maintain the quality of the photo-mask.